Reduce chemicals and packaging (and save money in the long-term) by using microfibre cloths, such as e-cloths, that only need water to clean. Use them in the kitchen instead of kitchen paper towel. If you do use kitchen towel, buy recycled and compost after use.
Bicarbonate of soda makes a good cleaner, mixed to a paste with a little water. It can also be used in the fridge or sprinkled on carpets to deodorise.
White vinegar or lemon juice works on limescale. Soak the shower head in a dish of vinegar (which can be stored in a covered container and used again the next time) and wrap a cloth soaked in vinegar round a tap spout.
Wiping the shower door after use will prevent a build-up of lime-scale and only takes seconds. Brush the loo daily to reduce the need for harsh chemicals.
Rinse out containers to use all of the product (I use up the dregs of washing liquid to soak doormats and other items that won't fit in the washing machine - Shirley).
If you do have any unwanted chemical cleaners at home, or garden chemicals such as weedkillers and pesticides, take them to the Household Recycling Centre for safe disposal (ask where to put them when you arrive). Never pour down the drain: a serious incident in 2013 on River Kennet, shows how much harm chemicals can do if disposed of thoughtlessly.